<?php
// +----------------------------------------------------------------------
// Csmmeet [ CSM系列公共源码 ]
// Author: chensm <chenshiming0802@163.com>
// Create by chensm at 2020-02-26
// +----------------------------------------------------------------------
namespace addons\csmonline\library;

class CsmUtils 
{
    public static function isNullOrBlank($str){
        if($str==null || $str==""){
            return true;
        }else{
            return false;
        }
    }
    
    public static function unescape($str)
    {
        $ret = '';
        $len = strlen($str);
        for ($i = 0; $i < $len; $i ++)
        {
            if ($str[$i] == '%' && $str[$i + 1] == 'u')
            {
                $val = hexdec(substr($str, $i + 2, 4));
                if ($val < 0x7f)
                    $ret .= chr($val);
                    else
                        if ($val < 0x800)
                            $ret .= chr(0xc0 | ($val >> 6)) .
                            chr(0x80 | ($val & 0x3f));
                            else
                                $ret .= chr(0xe0 | ($val >> 12)) .
                                chr(0x80 | (($val >> 6) & 0x3f)) .
                                chr(0x80 | ($val & 0x3f));
                                $i += 5;
            } else
                if ($str[$i] == '%')
                {
                    $ret .= urldecode(substr($str, $i, 3));
                    $i += 2;
                } else
                    $ret .= $str[$i];
        }
        return $ret;
    }
}